ציטירנדיקער פּירוש אויף שמות 21:11

More than him - since she acquires herself with all these modes, as well as through signs indicating puberty, as we derived earlier (Kiddushin 4a:3) from "Then shall she go out for nothing." (Exodus 21:11)

יתירה עליו אמה – that she purchases herself with all of these signs of [feminine] adulthood, as we derive from (Exodus 21:11), “she shall go free,” they use the additional word [of] “going free” for the purpose of widening the scope of the law, that she goes free with [the appearance] of signs [of female adulthood].

בקידושיה בכסף – for the money of her betrothal is his (i.e., the father’s) as it is written concerning the Hebrew maidservant (Exodus 21:11): “she shall go free, without payment,” and we expound, that there is no money to this master, meaning to say to the master who purchased her that she left him gratuitously/for no reason with the signs of young womanhood, but if another master has money and the father appointed him, the money of her betrothal/sanctification is his, eve when she is a young woman until she becomes an adult woman.